The overall goal of the research will be to build on our progress in creating an integrated system for ablation of prostatic tissue incorporated advanced designs for the ablation prostate tissue, and ultimately prostatic carcinoma, in a rapid, precise fashion under MRI guidance. Applicators will either be directly inserted into the prostate gland through the perineum (interstitial applicators) of through the urethra (transurethral). Several new designs for transurethral applicators, designed to maximize speed and precision of treatment will be designed and tested. A system to perform automated rotational and linear mechanical control of applicators during in vivo treatments will be constructed. Systems for preventing rectal injury, including a endorectal cooling system using circulating water, and procedures for providing acoustic blocking between the prostate and rectum will be further developed. Further enhancements to our successful system for MR temperature imaging (MRTI) will be achieved using a referenceless approach, 3 point Dixon, multiple readouts per TR, and phased array imaging to create an optimal real-time system for monitoring of ablation. The research plan envisages a heirarchical series of experiments, with initial development and testing of all the component technologies described above, to be followed by extensive in vivo studies of prostate ablation in a canine model. In these experiments, different applicators and protocols will be tested and compared for performance in performing rapid, controlled ablation. MRTI techniques will be tested in these trials as well, with correlative thermocouple monitoring to assess accuracy. Improved histologic analysis techniques for resected prostate glands and periprostatic tissues following treatments will allow accurate correlation of MRTI data and post-treatment MR images, and a chronic model of prostatic ablation (7 or more days) will be assessed. At the completion of this work, we plan to have completely defined an integrated system suitable for clinical ablation of prostatic tissue and prostate cancer.